Cut-throat businessman favouring tree receiving support (9)
I believe the answer is:
profiteer
'cut-throat businessman' is the definition.
(someone out to make a profit)
'favouring tree receiving support' is the wordplay.
'favouring' becomes 'pro' (I've seen this before).
'tree' becomes 'fir' (fir is a kind of tree).
'receiving' is an insertion indicator.
'support' becomes 'tee' (tee is a kind of support).
'fir' placed around 'tee' is 'fiteer'.
'pro'+'fiteer'='PROFITEER'
(Other definitions for profiteer that I've seen before include "Make too much money" , "Overcharge" , "Make money unfairly" , "insider trader?" , "Make excessive gains" .)